Press Releases

POLYFUSE Ultra Low Resistance LoRho SMD Resettable PPTC Provides Fast Overcurrent Protection, Resets Automatically


0402 Package Offers Smallest SMD PPTC Device on the Market

CHICAGO--(BUSINESS WIRE)-- Littelfuse, Inc., the global leader in circuit protection, today announced its new resettable PPTC (Polymer Positive Temperature Coefficient) resistor series. The new product line is designed for high speed overcurrent protection in applications that require ultra-low internal resistance, ultra-low voltage drop and minimal power dissipation. The POLYFUSE® LoRho™ Surface Mount Resettable PPTC series offers ultra-low internal resistance while maintaining the high level electrical characteristics and performance provided by standard PPTC products from Littelfuse.

Littelfuse LoRho PPTC devices provide overcurrent protection against fault current surges by limiting the electrical current flowing through the device. When a fault current flows through the device, it generates heat, which causes the device’s internal resistance to rise rapidly, limiting the current flow to the circuit downstream to a safe level. After the overcurrent condition passes, the device’s internal resistance drops back to its normal low resistance state, restoring the circuit to its normal operating condition. By resetting automatically, this device offers a low maintenance alternative to one-time fuses for overcurrent protection.

Matthew Chan, Global Product Manager for the Littelfuse LoRho PPTC Series, says, “This series, with its ultra-low internal resistance characteristics, offers the ideal solution for overcurrent protection of electronic product applications where ultra-low voltage drop and minimal power dissipation are also critical.”

In comparison with standard SMD PPTCs on the market, Littelfuse LoRho SMD PPTCs have significantly lower internal resistances (from 45 percent to more than 60 percent lower) and drastically reduced thicknesses (more than 50 percent thinner).

The LoRho Surface Mount Resettable PPTC series offers circuit designers a variety of key benefits:

  • Smallest footprint PPTC in the market, available in sizes as small as 0402, which helps saves board space, allowing more room for other components.
  • Offer high design flexibility, making it easy to design-in the most suitable device for the application by providing the industry’s broadest range of hold current ratings (100mA to 7A).
  • A very thin height profile makes the series suitable for use in compact portable electronics.
  • Their fast response to fault currents provides secure protection for sensitive electronic products.
  • By resetting automatically, they provide a low maintenance alternative to one-time fuses for overcurrent protection.
  • RoHS compliant, lead free, halogen free, and UL and TUV recognized, which ensures they are environmentally friendly and compliant with international safety standards.
  • Compatible with high temperature solders, so they meet lead-free soldering requirements.

Littelfuse LoRho SMD PPTCs offer the best overcurrent protection solution for meeting today’s low power dissipation requirements of Li ion/Li Polymer battery packs. Other applications for these devices include handheld electronics (smartphones, mp3 players, digital cameras, video cameras, and e-readers), computer and peripherals (desktop and notebook computers, tablet PCs, audio/data/video cards, LCD and LED displays, USB thumb drives and data storage devices, USB 3.0 and 2.0 ports, PC motherboards), and gaming consoles and accessories.

The POLYFUSE LoRho PPTC Resistor series is available in quantities of 2,000–10, 0000 in standard tape and reel packaging.

Technical Contact:
Matthew Chan
Product Manager, LoRho PPTCs

About Littelfuse

Founded in 1927, Littelfuse, Inc., the worldwide leader in circuit protection, offers the industry’s broadest and deepest portfolio of circuit protection products and solutions. Littelfuse devices protect products in virtually every market that uses electrical energy, from consumer electronics to automobiles to industrial equipment. In addition to its Chicago, Illinois, world headquarters, Littelfuse has more than 30 sales, distribution, manufacturing and engineering facilities in the Americas, Europe and Asia. Technologies offered by Littelfuse include Fuses; Gas Discharge Tubes (GDTs); Positive Temperature Coefficient Devices (PTCs); Protection Relays; PulseGuard® ESD Suppressors; SIDACtor® Devices; Silicon Protection Arrays (SPA™); Switching Thyristors; TVS Diodes and Varistors. The company also offers a comprehensive line of highly reliable Electromechanical and Electronic Switch and Control Devices for commercial and specialty vehicles, as well as Protection Relays and underground Power Distribution Centers for the safe control and distribution of electricity.

For more information, please visit the Littelfuse website:

Link to high resolution image

Littelfuse, Inc.
Rhonda Stratton, Marketing Communications Manager, 773-628-0644

Source: Littelfuse, Inc.